Fine coal desulphurization by leaching with bromine containing hydrobromic acid

Sulphur extraction from coal by leaching with bromine-containing aqueous hydrobromic acid has been investigated in the temperature range from ambient to 120 °C. This procedure was found to be selective for the removal of high levels of sulphate and pyritic sulphur within a few minutes of leaching, while no significant reduction of the organic sulphur could be observed. Leaching led to an appreciable reduction of the ash yield and the up-take of substantial quantities of bromine. The bromine can be removed as hydrogen bromide by thermal treatment under nitrogen, without significant loss of volatile matter; for reduction of the bromine level to below 0.1 wt%, treatment for at least 1 h at ≈ 500 °C was needed.     

钯回收网在双加压硝酸装置上的应用

本文介绍了山西化肥厂双加压硝酸装置铂网及钯回收网的使用情况，并对钯回收网的应用进行了分析。     

The influence of sulfur dioxide on propane oxidation activity over supported platinum and palladium

Earlier studies have shown that sulfur dioxide and metal-support interaction can strongly influence propane oxidation over platinum. In particular, oxidation activity is enhanced when platinum is supported on sulfated -alumina or zirconia compared to -alumina. Therefore, it is of interest to compare the performance of palladium under the same experimental conditions. Four model catalysts were examined: Pt/-alumina, Pt/zirconia, Pd/-alumina and Pd/zirconia. The metal loading was kept at or below 0.05 wt% to emphasize changes in activity attributable to metal-support interaction. Reaction rates were measured with and without sulfur dioxide. Surface sulfation was analyzed by measuring acid strength and evaluating spectra obtained by Fourier-transform infrared spectroscopy. In contrast to platinum, sulfation does not promote propane oxidation on Pd/-alumina, and Pd/zirconia is less active than Pd/-alumina.     

Surface modification of macroporous Al2O3 tubes with carbon-doped TiO2 intermediate layer and preparation of highly permeable palladium composite membranes for hydrogen separation

ABSTRACT

To prepare H₂-permeable palladium composite membranes, a novel carbon-doped microporous TiO₂ intermediate layer was introduced to modify the surface of macroporous Al₂O₃ substrates. The Pd/TiO₂–C/Al₂O₃ membrane was prepared via electroless plating, and thereafter, carbon residue in the intermediate layer was removed by calcination in air, yielding a Pd/TiO₂/Al₂O₃ membrane. Experimental results indicate that the carbon residue shrinks the pore size of the intermediate layer and facilitates a decrease of membrane defects. Additionally, carbon removal induces a higher effective membrane area at the permeate side, which enhances hydrogen permeability. Furthermore, the apparent activation energy (E_A) and stability of the as-prepared Pd/TiO₂/Al₂O₃ membrane were investigated.     

Time-of-flight studies on catalytic model reactions

Time-of-flight spectroscopy (TOF) and REMPI-TOF (resonance enhanced multi-photon ionization-TOF) were applied to measure the angular and translational energy distribution, as well as the internal state resolved energy distribution of desorption and reaction products on some model systems. Desorption of hydrogen and deuterium from clean and modified Pd(111) surfaces was studied, where the palladium sample was part of a permeation source. Water formation by reaction of oxygen with hydrogen on palladium was investigated by using different types of hydrogen supply: molecular H₂ exposure and atomic H exposure from the gas phase, as well as H exposure by permeating hydrogen. Vanadium oxide nanostructures on Pd(111) were prepared and the influence on D₂ desorption and D₂O production was investigated with the permeation technique. Additionally, deuterium desorption from sulfur and oxygen covered V(111) and V(100) surfaces was studied by TOF and REMPI-TOF spectroscopy. From the TOF spectra information concerning the reaction and desorption dynamics (activation barriers) could be gained.     

A highly stable and efficient catalyst for direct synthesis of LPG from syngas

Liquefied petroleum gas (LPG) fuel was directly synthesized from syngas over a hybrid catalyst which contained a methanol synthesis catalyst and zeolite. The new hybrid catalyst composed of (Pd–Ca/SiO₂) and β-zeolite, showed a high activity and selectivity for LPG production. X-ray diffraction (XRD) characterization of the catalyst was used to analyze the deactivation of (Pd–Ca/SiO₂)/β-zeolite.     

In situ ellipsometric study of a palladium catalyst during the oxidation of methane

Ellipsometry is used to follow the growth of a PdO layer on the surface of a thick Pd-film catalyst during methane oxidation at 500°C. The oxide layer that develops under rich conditions (excess CH₄) is quite porous and roughens with time. Little CO is formed during this period, but the CO₂ formation rate increases until spontaneous oscillations develop, which correlate with changes in the ellipsometric data. These changes indicate that the porous oxide rapidly converts to a metal-rich state, which has decreased catalytic activity, and then slowly reoxidizes.     

二氧化硫浸锰制备高纯碳酸锰

采用湘潭低品位的贫软锰矿为原料，对二氧化硫气体湿法浸锰、浸出液除杂、碳化结晶制备高纯碳酸锰的工艺进行了研究。实验得到二氧化硫浸锰的最佳工艺条件为：浸锰温度150～155℃，液固质量比3：1，二氧化硫体积分数6％～7％、流速1．5～2．0mL／min，浸锰时间3．0～3．5h。按该条件浸锰，锰的浸出率可达95％以上。该工艺为贫软锰矿的开发利用及有色金属冶炼厂二氧化硫废气的综合治理开辟了一条新途径。     

表面活性剂对HCl-FeCl3溶液中锌精矿在浆萃取浸出率的影响

The effects of surfactant on the solvent extraction in leaching sphalerite were investigated. It is found that sodium dodecyl sulfonate is the effective surfactant in improving the zinc recovery from sphalerite in the aqueous FeCl3-HCl-tetrachloroethylene system. Through the measurements of surface tension and viscosity of the sphalerite slurry modified with different surfactants, it is concluded that sodium dodecyl sulfonate in the concentration range of 0.05 to 0.2g L-1 can improve the viscosity of sphalerite slurry in the water, decrease the surface tension of leaching solution, prevent the aggregation of ore particles, and give very high zinc extraction .     

8─羟基喹啉─5─磺酸柱前衍生反相HPLC分离测定痕量Al（Ⅲ）、Co（Ⅲ）、Fe（Ⅲ）和Pd（Ⅱ）

本文采用８－羟基喹啉－５－磺酸（ＨＱＳ）为柱前衍生试剂，用含有１０ｍｍｏｌ·Ｌ－１的四丁基溴化铵（ＴＢＡ＋Ｂｒ－）、７．５×１０－５ｍｏｌ·Ｌ－１的ＥＤＴＡ和２０ｍｍｏｌ·Ｌ－１的ｐＨ５．６乙酸－乙酸钠缓冲溶液的甲醇－水（４５：５５，Ｖ／Ｖ）溶液为流动相，以Ｃ１８硅烷化载体为固定相，１６ｍｉｎ内分离测定了Ｃｏ（Ⅲ）、Ｆｅ（Ⅲ）、Ａｌ（Ⅲ）和Ｐｄ（Ⅱ）的ＨＱＳ的配合物、信噪比为３时，检出限分别为：Ｃｏ（Ⅲ）０．９ｐｐｂ、Ｆｅ（Ⅲ）１．５ｐｐｂ和Ｐｄ（Ⅱ）５．４ｐｐｂ，方法灵敏度高，干扰少，用于测定试剂级盐酸，硝酸和中国红茶样品中的这些离子，结果良好。